Multipurpose high school physics experiment teaching instrument

Abstract

A multipurpose high school physics experiment teaching instrument comprises a base and a simply supported beam support arranged on the base, the center of an upper cross beam of the simply supported beam support is fixedly connected with a center fixed shaft horizontally extending front and back, a protractor is fixed on two stand columns of the simply supported beam support, the center fixed shaft penetrates through the center original point of the protractor, and the center fixed shaft is fixed on the two stand columns of the simply supported beam support. A first swing rod is in sliding fit with the forward extending section of the center fixed shaft, a second swing rod, a third swing rod and a fourth swing rod are sequentially in sliding fit with the backward extending section of the center fixed shaft in the axial direction, and each swing rod comprises a balance rod extending upwards and a steel ball connecting rod extending downwards. The balancing rod and the corresponding steel ball connecting rod are the same in length and are coaxial, a photoelectric door and a timer are arranged on the base, and four foot pads are arranged at the lower end of the base.

Description

Technical Field

[0001] The utility model belongs to the technical field of teaching demonstration equipment, in particular to a multi-purpose high school physics experiment teaching instrument. Background Art

[0002] In high school physics, the study of simple pendulum, conservation of system mechanical energy, and conservation of system momentum are three very important knowledge points. In the learning process, using teaching instruments to demonstrate the experimental process to students is an indispensable link. It not only adds to the fun of learning, but also allows students to see the experimental phenomena more intuitively and deepen students' impression of knowledge.

[0003] At present, the instruments for the simple pendulum experiment include a stopwatch, a ruler, and a simple pendulum. During the experiment, a small ball is first hung on a bracket using a thin wire. During the experiment, the thin wire is kept tight, and the small ball is pulled up to a certain angle and then released from rest, so that students can observe the experimental phenomena and study the relationship between the period of the ball's swing and the length of the pendulum. However, the small ball is prone to produce a conical pendulum phenomenon when it swings, resulting in inaccurate experimental results and affecting students' understanding of the experiment. At the same time, the system mechanical energy conservation experiment and the system momentum conservation experiment are also the key points and difficulties of high school physics, and each experiment corresponds to an instrument. When learning the corresponding experiments in class, three instruments need to be used to demonstrate them separately. At the same time, if you want the students in the back row to see clearly, the instruments need to be large enough, and the teachers need to carry them separately, which not only increases the workload of the teachers, but also takes up space in the classroom. Summary of the invention

[0004] The purpose of the utility model is to propose a multi-purpose high school physics experiment teaching instrument to address the problems existing in the prior art. The instrument can demonstrate three experiments of high school physics, namely, Experiment 1: Demonstration and application demonstration experiment of simple pendulum period, Experiment 2: Experiment to explore the law of conservation of mechanical energy of the system, Experiment 3: Demonstration experiment of conservation of momentum phenomenon of the system. Each swing rod of the teaching instrument is slidably matched with the central fixed axis through a bearing. Compared with the thin wire suspended steel ball in the prior art, the teaching instrument avoids the conical pendulum phenomenon. Compared with the prior art that one experiment only corresponds to one instrument, the instrument only needs to change the direction to demonstrate other experiments, which is more convenient for teachers to operate. The teaching instrument is large in size and can be seen clearly by students in the back row.

[0005] The purpose of the utility model is achieved in this way.

[0006] A multi-purpose high school physics experiment teaching instrument, comprising a base and a simply supported beam bracket arranged on the base, wherein the center of the cross beam on the simply supported beam bracket is fixedly connected to a central fixed axis extending horizontally forward and backward, and a protractor is fixed on two upright posts of the simply supported beam bracket, wherein the central fixed axis passes through the central origin of the protractor, and the forward extension section of the central fixed axis is slidably matched with a first swing rod, and the backward extension section of the central fixed axis is slidably matched with a second swing rod, a third swing rod, and a fourth swing rod in sequence along the axial direction, wherein each swing rod comprises a balancing rod extending upward and a steel ball connecting rod extending downward, wherein the balancing rod and the corresponding steel ball connecting rod have the same length and are coaxial, and the first The steel ball connecting rod of the swing rod is fixedly connected to a big ball a and a big ball b, the center position of the big ball a is higher than the center position of the big ball b, the lower end of the steel ball connecting rod of the second swing rod is fixedly connected to a big ball c, the lower end of the steel ball connecting rod of the third swing rod is fixedly connected to a small ball, the center of the big ball c and the center of the small ball are at the same height, the lower end of the steel ball connecting rod of the fourth swing rod is fixedly connected to a big ball d, the center position of the big ball d is higher than the center position of the big ball c, the big balls a, big balls b, big balls c and big balls d are equal in size, made of the same material, and are all larger than the diameter of the small ball, a photoelectric gate and a timer are provided on the base, and four foot pads are provided at the lower end of the base.

[0007] Furthermore, each swing arm is slidably matched with the central fixed axis through a bearing, the inner ring of the bearing is fixedly connected to the central fixed axis, the upper end of the outer ring of the bearing is welded and fixed to the balance rod extending upward, and the inner ring of the bearing is welded and fixed to the steel ball connecting rod extending downward.

[0008] Furthermore, the inner ring of the bearing is interference fit or welded to the central fixed shaft.

[0009] Furthermore, the lower ends of the large ball a, large ball b, large ball c, large ball d, and small ball are fixedly connected with a nut, the steel ball connecting rod is a long screw rod, and the large ball a, large ball b, large ball c, large ball d, and small ball are threadedly matched with the steel ball connecting rod through the nut.

[0010] Furthermore, four rollers are provided at the lower end of the base, the foot pads are threadedly matched with the base, and the height of the foot pads is higher than the height of the rollers.

[0011] Furthermore, the roller is a bearing.

[0012] Furthermore, the big ball a, big ball b, big ball c, big ball d and small ball are all chrome-plated iron balls.

[0013] By adopting the above scheme, the multi-purpose high school physics experiment teaching instrument of the utility model can demonstrate multiple physics experiments. There is no need to replace a teaching instrument for each experiment, which saves the teacher's classroom operation time; the teaching instrument has a simple structure, and the simple structure can also deepen students' understanding of physics experiments; the swing rod of the teaching instrument slides with the central fixed axis through a bearing, thereby avoiding the conical pendulum phenomenon when the steel ball swings; and each swing rod is provided with a balance rod extending upward, which can offset the error caused by the mass of the steel ball connecting rod. The teaching instrument is easy for teachers to operate, has a large size, and can be clearly seen by students in the back row.

[0014] The utility model is further described below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an assembly drawing of the base, simply supported beam bracket and central fixed axis of the utility model.

[0016] Figure 2 It is a front view of the utility model.

[0017] Figure 3 It is a rear view of the utility model.

[0018] Figure 4 for Figure 2 Schematic diagram of direction A.

[0019] Explanation of the accompanying drawings: base 1, simply supported beam bracket 2, cross beam 3, central fixed axis 4, protractor 5, column 6, first swing arm 7, second swing arm 8, third swing arm 9, fourth swing arm 10, balance rod 11, steel ball connecting rod 12, large ball a131, large ball b132, large ball c133, large ball d134, small ball 14, photoelectric gate 15, timer 16, foot pad 17, bearing 18, nut 19, roller 20. DETAILED DESCRIPTION

[0020] See also Figures 1 to 4A multi-purpose high school physics experiment teaching instrument includes a base 1 and a simply supported beam bracket 2 arranged on the base 1, the center of the cross beam 3 on the simply supported beam bracket 2 is fixedly connected to a central fixed axis 4 extending horizontally forward and backward, a protractor 5 is fixed on two columns 6 of the simply supported beam bracket 2, the arc section of the protractor 5 is downward, and the arc section is provided with scale lines for measuring angles, and the horizontal section of the protractor 5 is upward, and the horizontal section is provided with scale lines for measuring lengths. The central fixed axis 4 passes through the central origin of the protractor 5. The forward extension section of the central fixed axis 4 is slidably matched with the first swing rod 7. The backward extension section of the central fixed axis 4 is slidably matched with the second swing rod 8, the third swing rod 9, and the fourth swing rod 10 in the axial direction. Each swing rod includes an upwardly extending balance rod 11 and a downwardly extending steel ball connecting rod 12. The balance rod 11 and its corresponding steel ball connecting rod 12 have the same length and are coaxial. The function of the balance rod 11 is to offset the error caused by the mass of its corresponding steel ball connecting rod 12, so as to make the experimental data more accurate. The steel ball connecting rod 12 of the first swing rod 7 is fixedly connected with large balls a131 and b132. The center position of the large ball a131 is higher than the center position of the large ball b132. The lower end of the steel ball connecting rod 12 of the second swing rod 8 is fixedly connected to a large ball c133, the lower end of the steel ball connecting rod 12 of the third swing rod 9 is fixedly connected to a small ball 14, the center of the large ball c133 and the center of the small ball 14 are at the same height, the lower end of the steel ball connecting rod 12 of the fourth swing rod 10 is fixedly connected to a large ball d134, the center of the large ball d134 is higher than the center of the large ball c133, the large balls a131, b132, c133 and d134 are of equal size and made of the same material, and are all larger than the diameter of the small ball 14, a photoelectric gate 15 and a timer 16 are provided on the base 1, and four foot pads 17 are provided at the lower end of the base 1.

[0021] Furthermore, each swinging rod is slidably matched with the central fixed shaft 4 through a bearing 18, the inner ring of the bearing 18 is fixedly connected to the central fixed shaft 4, the upper end of the outer ring of the bearing 18 is welded and fixed to the balance rod 11 extending upward, and the inner ring of the bearing 18 is welded and fixed to the steel ball connecting rod 12 extending downward. The advantage of using the bearing 18 is to avoid the conical pendulum phenomenon when each ball swings, making the experimental data more accurate. Furthermore, the inner ring of the bearing 18 is interference fit or welded and fixed to the central fixed shaft 4 to prevent it from coming out, thereby improving the working stability of each swinging rod.

[0022] Furthermore, the lower ends of the large ball a131, large ball b132, large ball c133, large ball d134, and small ball 14 are fixedly connected with a nut 19, and the steel ball connecting rod 12 is a long screw rod. The large ball a131, large ball b132, large ball c133, large ball d134, and small ball 14 are threadedly matched with the steel ball connecting rod 12 through the nut 19. The nut 19 can not only fix the large ball 13 and the small ball 14, but also prevent the axial movement of each ball during swinging, and can also be disassembled and replaced.

[0023] Furthermore, four rollers 20 are provided at the lower end of the base 1, and the foot pad 17 is threadedly matched with the base 1. The height of the foot pad 17 is higher than the height of the roller 20, and the foot pad 17 is easy to disassemble and assemble. The foot pad 17 supports and fixes the entire instrument. When the experiment requires the entire teaching instrument to move on a horizontal plane, the four foot pads 17 are removed to make the roller 20 contact the ground. Furthermore, the roller 20 is a bearing, and the bearing material is widely available, low in cost, and easy to replace.

[0024] Furthermore, the large ball a131, the large ball b132, the large ball c133, the large ball d134, and the small ball 14 are all chrome-plated iron balls.

[0025] The utility model is a multi-purpose high school physics experimental teaching instrument, which can demonstrate three experiments, namely, experiment one: a simple pendulum cycle demonstration and application demonstration experiment, experiment two: a system mechanical energy conservation law exploration experiment, and experiment three: a system momentum conservation phenomenon demonstration experiment. The experiments are as follows.

[0026] Experiment 1: Simple pendulum period demonstration and application demonstration experiment (this experiment includes three sub-experiments)

[0027] (1) Demonstration experiment on the relationship between the period of a simple pendulum and its length: This experiment uses large ball c133 and large ball d134. The other large and small balls are in a naturally suspended state and do not participate in the experiment.

[0028] The position of the center of the big ball d134 is higher than that of the center of the big ball c133. According to the scale line for measuring the angle below the protractor 5, the big balls c133 and d134 are deviated from the same angle and released from rest at the same time. At this time, students can intuitively observe that the big ball d134 returns to the initial position first, and the big ball c133 returns to the initial position later.

[0029] Corresponding simple pendulum period formula (The formula comes from the first volume of the optional compulsory high school physics course published by the People's Education Press, Chapter 2 "Mechanical Vibration", Section 4, page 46 "Simple Pendulum"; where T is the period, and the period T is the time it takes for the iron ball to return to the initial point after a reciprocating motion starting from a certain position; l is the pendulum length, and the pendulum length l is the distance from the center of the iron ball to the rotation center of the corresponding swing rod, g is the local acceleration of gravity, and π is pi). Combined with the above experimental phenomena, let students realize that the period of a simple pendulum is related to the pendulum length. The smaller the pendulum length, the smaller the period, and the longer the pendulum length, the longer the period.

[0030] (2) Demonstration experiment that the period of a simple pendulum is independent of mass: This experiment uses a large ball c133 and a small ball 14. The other large and small balls are in a naturally suspended state and do not participate in the experiment.

[0031] The center of the big ball c133 is at the same height as the center of the small ball 14. According to the scale line for measuring the angle below the protractor 5, the big ball c133 and the small ball 14 are deviated from the same angle and released from rest at the same time. At this time, students can intuitively observe that the big ball c133 and the small ball 14 return to their initial positions at the same time.

[0032] Corresponding simple pendulum period formula Based on the above experimental phenomena, let students realize that the period of a simple pendulum has nothing to do with the mass of the iron ball.

[0033] (3) Experiment to explore the period formula of a simple pendulum: This experiment uses the large ball c133, and the other large and small balls are in a naturally suspended state and do not participate in the experiment. Move the photogate 15 to the bottom of the large ball c133 and fix it, and connect the timer 16 to the photogate 15.

[0034] There are two ways to complete this experiment.

[0035] Method 1:

[0036] S1, record the pendulum length l of the large ball c133 according to the length measuring scale line on the protractor 5;

[0037] S2, take the local gravity acceleration g = 9.7m / s 2 , take π = 3.14, substitute it into the pendulum length l in step S1, and calculate The result is the theoretical period of the large ball c133;

[0038] S3, open the photoelectric gate 15 and the timer 16, deviate the big ball C133 by a certain small angle (the small angle is ≤ 5°) and then release it from rest, so that the big ball C133 undergoes a reciprocating motion, record the continuous time t of the lower end of the second swing rod 8 blocking the light twice, t is half of the actual period of the swing of the big ball C133, calculate 2t, and the result is the actual period of the big ball C133;

[0039] S4, let students compare the theoretical period and actual period of the big ball c133 in steps S2 and S3. The results show that the theoretical period of the big ball c133 is approximately equal to the actual period. Through the above experimental steps and calculation process, students can more intuitively understand the application of the simple pendulum period formula and have a deeper understanding of the simple pendulum period formula. The error between the two is caused by the influence of air resistance and the friction of this experimental instrument. Because this teaching instrument is not a precise and strict scientific instrument, it is only used for classroom demonstration, and the experiment is carried out in an atmospheric environment, so this influence can be ignored.

[0040] Method 2:

[0041] S1, open the photoelectric gate 15 and the timer 16, deviate the big ball C133 from a certain angle and then release it from rest, so that the big ball C133 undergoes a reciprocating motion, record the continuous time t of the lower end of the second swing rod 8 blocking the light twice, t is half of the actual period of the swing of the big ball C133, calculate 2t=T, and the result is the period T of the big ball C133;

[0042] S2, take the local gravity acceleration g = 9.7m / s 2 , take π = 3.14, and the period T of the large ball c133 in step S1, and substitute it into the simple pendulum period formula Calculate the theoretical pendulum length of the large ball c133;

[0043] S3, record the actual pendulum length of the large ball c133 according to the scale line measuring the length above the protractor 5;

[0044] S4, let students compare the theoretical pendulum length and actual pendulum length of the big ball c133 in steps S2 and S3. The results show that the theoretical pendulum length of the big ball c133 is approximately equal to the actual pendulum length. Through the above experimental steps and calculation process, students can more intuitively understand the application of the simple pendulum period formula and have a deeper understanding of the simple pendulum period formula. The error between the two is caused by the influence of air resistance and the friction of this experimental instrument. Because this teaching instrument is not a precise and strict scientific instrument, it is only used for classroom demonstration, and the experiment is carried out in an atmospheric environment, so this influence can be ignored.

[0045] Experiment 2, exploration of the law of conservation of mechanical energy of the system: This experiment uses large ball a131 and large ball b132, and the other large balls and small balls are in a naturally suspended state and do not participate in the experiment. The photoelectric gate 15 is moved to the bottom of the large ball b132 and fixed, and the timer 16 is connected to the photoelectric gate 15. In this embodiment, the pendulum length of the large ball b132 is adjusted to be twice the pendulum length of the large ball a131 for the purpose of facilitating calculation; and the large ball b132 is as close as possible to the lower end of the steel ball connecting rod 12, in order to make the speed measured by the photoelectric gate 15 closer to the actual speed of the large ball b132.

[0046] S1, according to the length measuring scale line on the protractor 5, record the pendulum length of the large ball a131 as l, and the pendulum length of the large ball b132 as 2l;

[0047] S2, make the big ball a131 and the big ball b132 in a naturally hanging state, which is the position of the two balls after swinging. The horizontal plane where the center of the big ball b132 is located is set as the reference plane, then the height of the big ball a131 after swinging is l, and the height of the big ball b132 after swinging is 0;

[0048] S3, according to the scale line for measuring angles below the protractor 5, pull up the big ball a131 and the big ball b132 to a certain angle, which is defined as the position before the two balls swing, and record the angle between the two big balls and the vertical direction as θ. The height of the big ball a131 before the swing is l-lcosθ+l, and the height of the big ball b132 before the swing is 2l-2lcosθ. The big balls a131 and b132 are stationary before the swing, so the speed of the big balls a131 and b132 before the swing is 0. The theoretical speed of the big ball b132 after the swing is defined as v, and the theoretical speed of the big ball a131 after the swing is defined as (Because the pendulum length of the big ball a131 is half of the pendulum length of the big ball b132), define the local gravity acceleration as g, and the masses of the big balls a131 and b132 are both m;

[0049] S4, release the two balls from rest, and calculate the time t when the steel ball connecting rod 12 blocks the photoelectric gate 15 when it swings to the lowest point for the first time, and the diameter d of the steel ball connecting rod 12. The v′ is the actual speed of the steel ball connecting rod 12;

[0050] S5, according to the mechanical energy conservation formula of a single ball swinging①: (The formula comes from the second volume of the compulsory high school physics course published by the People's Education Press, Chapter 8 "Law of Conservation of Mechanical Energy", Section 5, page 46 "Experiment: Verification of the Law of Conservation of Mechanical Energy", where m is the mass of the ball, g is the local acceleration of gravity, h1 is the height of the ball before the swing, h2 is the height of the ball after the swing, v1 is the speed of the ball before the swing, v2 is the speed of the ball after the swing; the reference plane is the horizontal plane where the center of the ball is located after the swing). Substitute the data of the big ball a131 in steps S2 to S4 into formula ① to obtain equation ②: The data of the big ball a131 include the height l-lcosθ+l of the big ball a131 before swinging, the height l of the big ball a131 after swinging, the speed 0 of the big ball a131 before swinging, and the theoretical speed of the big ball a131 after swinging. Gravitational acceleration g, mass m of big ball a131, substitute the data of big ball b132 in steps S2 to S4 into formula ① to obtain equation ③: The data of the big ball b132 include: the height of the big ball b132 before the swing is 2l-2lcosθ, the height of the big ball b132 after the swing is 0, the speed of the big ball b132 before the swing is 0, the theoretical speed v of the big ball b132 after the swing, the gravitational acceleration g, and the mass m of the big ball b132;

[0051] S6, add the left side of the equal sign of equation ② and equation ③ in S5, and add the right side of the equal sign to obtain equation ④: The equation ④ is the mechanical energy conservation equation of the system composed of the large ball a131 and the large ball b132;

[0052] S7, after moving the terms of equation ④ in S6 and simplifying it, we get equation ⑤: In the equation ⑤, v represents the theoretical large ball speed v;

[0053] S8, repeat the above steps several times, adjust the angle θ between the two balls and the vertical direction, and define the local gravity acceleration g = 9.7m / s 2 , the data of multiple experiments are statistically analyzed, and the data are shown in Table 1; according to the experimental data of the applicant, the speed of the theoretical large ball b132 is approximately equal to the speed of the actual steel ball connecting rod 12, and the errors of multiple experiments are less than 3%. Through the above experimental steps and calculation process, students can more intuitively see the demonstration experiment of the law of conservation of mechanical energy of the system, and have a deeper understanding of the formula. The error between the two is the influence of air resistance, friction of this experimental instrument, etc., because this teaching instrument is not a precise and strict scientific instrument, it is only used for classroom demonstration, and the experiment is carried out in an atmospheric environment, so this influence can be ignored.

[0054] Table 1 Data Statistics

[0055]

[0056] Experiment three, demonstration experiment of conservation of system momentum: any ball can be used in this experiment, and the other large and small balls are in a naturally hanging state and do not participate in the experiment (if large ball a131 or large ball b132 is used, the other large ball of the first swing rod 7 can be removed), the four foot pads 17 at the lower end of the base 1 are removed, and the four rollers 20 are in contact with the horizontal ground.

[0057] First, let the students make a guess. According to the momentum conservation formula m1v1=m2v2 (the formula comes from the first volume of the optional compulsory high school physics course published by People's Education Press, Chapter 1 "Law of Conservation of Momentum", Section 4, Page 17 "Experiment: Verification of the Law of Conservation of Momentum", where m1 is the mass of the moving car before the collision, v1 is the instantaneous velocity of the object before the collision, m2 is the mass of the stationary car before the collision, and v2 is the instantaneous velocity of the stationary car after the collision), the various quantities of the momentum conservation formula correspond to the following in this experiment: m1 is the mass of the swinging ball, v1 is the average velocity of the swinging ball, m2 is the mass of the system after the swinging ball is removed from the teaching instrument of this patent, and v2 is the average velocity of the system after the swinging ball is removed from the teaching instrument of this patent. In theory, if the iron ball is deflected by a certain angle and released from rest, the teaching instrument of this patent will move in the opposite direction of the swing of the iron ball, and the speed of the teaching instrument of this patent is less than the speed of the swing of the iron ball. The teacher then demonstrated the experiment and found that the experimental phenomenon was consistent with the guess.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A multi-purpose high school physics experiment teaching instrument, characterized in that: The invention comprises a base (1) and a simply supported beam support (2) arranged on the base (1), wherein the center of a cross beam (3) on the simply supported beam support (2) is fixedly connected to a central fixed axis (4) extending horizontally forward and backward, and a protractor (5) is fixed on two upright posts (6) of the simply supported beam support (2), wherein the central fixed axis (4) passes through the central origin of the protractor (5), and a first swinging rod (7) is slidably matched on the forward extending section of the central fixed axis (4), and a second swinging rod (8), a third swinging rod (9), and a fourth swinging rod (10) are slidably matched in the axial direction on the backward extending section of the central fixed axis (4), and each swinging rod comprises a balancing rod (11) extending upward and a steel ball connecting rod (12) extending downward, wherein the balancing rod (11) and the corresponding steel ball connecting rod (12) are of the same length and coaxial, and a large ball a (131) and a large ball b (132) are fixedly connected to the steel ball connecting rod (12) of the first swinging rod (7). 2), the center position of the large ball a (131) is higher than the center position of the large ball b (132), the lower end of the steel ball connecting rod (12) of the second swing rod (8) is fixedly connected to a large ball c (133), the lower end of the steel ball connecting rod (12) of the third swing rod (9) is fixedly connected to a small ball (14), the center of the large ball c (133) and the center of the small ball (14) are at the same height, and the lower end of the steel ball connecting rod (12) of the fourth swing rod (10) is fixedly connected to a large ball c (133). A large ball d (134) is fixedly connected, the center of the large ball d (134) is higher than the center of the large ball c (133), the large balls a (131), b (132), c (133) and d (134) are of equal size and made of the same material, and are all larger than the diameter of the small ball (14), the base (1) is provided with a photoelectric switch (15) and a timer (16), and the lower end of the base (1) is provided with four foot pads (17).

2. The multi-purpose high school physics experiment teaching instrument according to claim 1 is characterized in that: Each swing rod is slidably matched with the central fixed shaft (4) via a bearing (18); the inner ring of the bearing (18) is fixedly connected to the central fixed shaft (4); the upper end of the outer ring of the bearing (18) is welded and fixed to the balance rod (11) extending upward; and the inner ring of the bearing (18) is welded and fixed to the steel ball connecting rod (12) extending downward.

3. The multi-purpose high school physics experiment teaching instrument according to claim 2 is characterized in that: The inner ring of the bearing (18) is interference fit or welded to the central fixed shaft (4).

4. The multi-purpose high school physics experiment teaching instrument according to claim 1 is characterized in that: The lower ends of the large ball a (131), the large ball b (132), the large ball c (133), the large ball d (134), and the small ball (14) are all fixedly connected to a nut (19); the steel ball connecting rod (12) is a long screw rod; the large ball a (131), the large ball b (132), the large ball c (133), the large ball d (134), and the small ball (14) are threadedly matched with the steel ball connecting rod (12) through the nut (19).

5. The multi-purpose high school physics experiment teaching instrument according to claim 1 is characterized in that: Four rollers (20) are also provided at the lower end of the base (1), the foot pad (17) is threadedly matched with the base (1), and the height of the foot pad (17) is higher than the height of the rollers (20).

6. The multi-purpose high school physics experiment teaching instrument according to claim 5 is characterized in that: The roller (20) is a bearing.

7. The multi-purpose high school physics experiment teaching instrument according to claim 1 is characterized in that: The large ball a (131), the large ball b (132), the large ball c (133), the large ball d (134), and the small ball (14) are all chrome-plated iron balls.

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